What purpose does the penis serve? Why is it that members of one species have no penis at all, while those of another have two? Why do they vary so much in shape and size? And where do vaginas, or the ...

A new study published in Science and led by Monash University biologists reveals that the energy cost of reproduction is far greater than previously believed. The research, led by Dr. Samuel C Ginther ...

The vast majority of animals need to breed to reproduce. But a small subset of animals can have offspring without mating. The process, called parthenogenesis, allows creatures from honey bees to ...

The energy invested in animal reproduction is as much as 10 times greater than previously estimated when the metabolic load of bearing and caring for offspring is accounted for, according to a new ...